Broadly speaking the proposed research involves developmental, regulatory, and pathological aspects of human immunological performance. Where animal models can be used similar studies are proposed if confident extrapolation to the human system seems possible. Specifically, this work represents a continuation of an effort to (1) analyze the cellular mechanisms involved in the control of T cell function; (2) analyze cellular immune performance in patients with a variety of diseases where immunological deviations may be important; and (3) an examination of the best methods for storing and studying human cells that have been suppressed by drugs in malignant disease or transplantation situations.